The present invention relates to a variable valve timing control apparatus of an internal combustion engine, which variably controls open and closing timing of an intake valve and/or an exhaust valve of the engine using an electric motor.
In recent years, there have been proposed and developed various variable valve timing control apparatuses, which improve control response and controllability of a relative rotational phase conversion between an engine crankshaft and a camshaft by transmitting a turning force of the electric motor to the camshaft through a speed reduction mechanism.
One such variable valve timing control apparatus is disclosed in Japanese Patent Provisional Publication No. 2010-255543 (hereinafter is referred to as “JP2010-255543”). In the variable valve timing control apparatus in JP2010-255543, as a power feed mechanism that feeds power to the electric motor, a power-feed brush provided at the electric motor side always makes sliding contact with a slip ring that is fixed to a cover member of the engine, thereby feeding the power to the electric motor.